GPUImageMovieWriter: fix bug when writing a movie with audio

Change from previous fix. We do want to allow audio to be written asynchronously, so instead we no longer invalidate the audio buffer in GPUImageMovie. Invalidating the buffer does not appear to be necessary.

Invalidating the buffer causes writing audio to fail because the buffer is invalidated by the time we come to write it to the AVAssetWriter asynchronously.
GPUImageMovieWriter: finishRecordingWithCompletionHandler must happen synchronously on video processing queue too

finishRecording runs synchronously, but if you call the method with a completion handler you don't. This results in a race condition to finish recording.
Merge branch 'refs/heads/movie-writer-finishRecordingWithCompletionHandler' into mymaster
Merge branch 'refs/heads/movie-writer-with-audio-bugfix' into mymaster
Revert "Hue: simpler hue filter using HSBFilter"

This reverts commit b865f202130f72c991bcac646eb21727dfd39d4c.

Conflicts:
	framework/Source/GPUImageHueFilter.m